Drill-steel bore-contracting means



I Aug. 26, 1930. G; c. PEARSON 1,774,290

I DRILL STEEL BORE CON'J'HACTING MEANS Filed July 28, 1928 2 Sheets-Sheet l Aug. 26, 1930. '6. c. PEARSON 1,774,290

I DRILL STEEL BORE CONTRACTING MEANS Filed July 28, 192 2 Sheets-sheaf. v2

Patented Aug, 26, 1930 U E STATES PATE oFFIcs GusrAv G. PEARSON, on DENVER; COLORADO, AssIeNon 'ro GARDNER-DENVER cont r NY, or DENVER, COLORADO, A conr'onn rron on DELAWARE DRI L-STEE nonnconrnnommemnnns Application filed July 28, 1928 V-Ser ialNo. 296,072.

' The present invention relates to means for v,

contracting the boresof drillsteel and pir ticularly'those of the so-cnlled McLellan? type, in which the bit is provided with'wings 5, formed byradially disposed cutting flanges.

When a bit of this :type issharpen'edand the hole punched therein,- it' often occurs faceeof the bit. v a

; vThe-object of the present invention is to 15 rovide a novel structure of "a, simple and hat the size ofthe hole orbore at thecutting end is soflargethat chips of rock broken 01f by; the cuttingedges enter and clogv the hole, thusmaln'ng it impossible to feed a suflicient amount; of water to thedrilling practical character for reducing the bore at 7 through the sharpeninggpr ocess. g H a A further and importanteobjecteistdpro vide a device of this character that can; be.

thezcutting end-after the bit-has passed mounted on the front endo the ordinary hammer. cylinder or --barrel of a pneumatic is we n m onlshowng assembledv structure for the above purpose: including a Preferred embodim t f th'euinf vention.

' .Figui'e 11st detail longitudinel sectional view on an 7 enlarged sc le of the dolly meclrs Figure 3 1st frontelevationofthe seine.- l Figured is adetail perspective view of v i the dollyrend the -associa'tedholding.

Figure 5 is a, longitudinal sectional view through a modifiedform of construction. V

Figure 6 is a front elevation. of the StlliCi tureshown Figure5.

Gtilisigiering.

closed inFigures'14 inclusive, at drill'stee'lj first the embodiinent disclamp is illustrated,"comprising a pair, of coacting jaws 7 and 8'that maybe oi any well known type andqa're designed to secure adrill steel In line-with these jews-isaJ pneumatic toolwhichinay beef any well knownor idesiredconstruction, and in the form shown involves a; cylinder member mounted on aibase .10; V This cylinder. inemg berincludes a barrel; 11,-having a piston chamber'12 and provided with an bore 1 3 in t me attain chamber; we chamber 1s a reciprocatory'hammer P1811011" 14;-a(:t11ated by motive fluid that isjdistribs uted thereto in any well: known manner.

Inthe rear end of" the counter-bore 13 is fitted a head disk 15; and abutting said head disk and fitted alsointothe chamber 13 in advance, thereof, is a bushing 16. This' bushinghasen outstanding annular fiange i is a imetalabearing disk QO'Yend a-yielding.

washer 21 of cork or other suitable compo? sition thatebsorbs se ne of the shockof the tool when in operation; The bushing 16 exte'nds. beyond the. flan e to form a chambered c 4 casing-22 hevinge, ront end wall 23 pro Vided with e central opening 24.

e A reciprocatory tappet 25is locat'edin the bushing 16 and chamber of the casingQQ, c and is provided with; enexternal annular flange 26 operating in echamberflTforniedin the rear end of the bushing 16. The

rear andyslightly reduced end 28 of the tappet extendsgthrough the head di'sk 15 intoaiposition to be struck by thepiston hammer 14, as indicatediin. Figure 2. The?- front end of the tappet is providedwithe Central longitudinal bore 29, and into said bore is detachablyfitted the stem'30of1e dolly; This dolly has an enlarged head 31 i that operates in the central opening 240i the front well 2 3jof the. casing. 22., The dolly. is held to i the' tappet preferably by means ofn' cross 11132 that extends through e trensversenopening 33 formed inthe tappet and engaging ine notch 341 for1ned in the stem '3O of the dolly, f'This cross pin pref- L erably extendsjthrough and beyondthe sides of the casing'z 22, 7 said casing "having longi- I tudinail slots :35 to. receive the pin zindcv perniit its inot ement upon the reciprocation of the tappet.v o

The front er proiecting' end of'the dolly headfil v is] upped as illustrated at 36; producingfegcirciilar cutting, edge 37, saidheed in effect acting as a die. It will also be noted particularly by reference to Figure 3 that the outer face of the front wall 23 of the casing 22 is provided with tapered grooves 38 that radiate from the front end of the dolly head 31, these grooves being shaped to receive and interfit with the radial cutting flanges 39 of the bit 40 of the drill steel 9.

The operation of the structure is as follows: When a steel has been properly sharpened and the bore thereof opened, it is clamped by the jaws 78, with its cutting edges or flanges 39 engaged in the grooves 38. Obviously this centers the bit 40 and the bore41 with respect to the dolly head 31, and incidentally acts as a firm abutment for the casing 22, and consequently for the entire pneumatic tool. If now the hammer piston 14 is put in operation, it will deliver rapidly repeated blows to the tappet 25 and these blows will be transmitted to the dolly head, thus driving the front end there'- of into the bit 40 and causing the metal around the bore to be forced inwardly, contracting the discharge end of'the bore as will be clear by reference to Figure 2.

It will be clear that this structure is an exceedingly simple one that can be mounted directly upon and in the end of" an ordinary cylinder member or pneumatic hammer barrel, and that it will effectively perform the function of contracting the bore of the steel. More than that, it will be obvious that'by using the grooves 38 to'center the bit of the steel, this centering action is made very accurate and steels with bits of different cross sectional areas will all fit to the.

same. 7

In Figures 5 and 6 a slightly modified form of structure is shown. Therein the barrel is designated 42, and the piston ham mer is shown at 43. The rear head disk fitted into the barrel designated 44 and the bushing cooperating therewith is illustrated at 45. In the present structure the chambered casing is'shown at 46 and is a separate element from the bushing 45, being formed of sections, the joint being shown at 47 held thereto by a retaining sleeve 48 bolted to the "flange 49' of the bushing 45 by cap screws 50 that pass through a flange 51 formed on the retaining. sleeve 48 through the fiange49 and being threaded into the front end of the barrel 42, as shown at 52. A shock-absorbing washer 53 is preferably interposed between the flanges 49 and 51. The chambered casing 46 is provided with an annular outstanding flange 54 and the retaining sleeve 48 has an inturned flange 55 located in advance of the flange 54. The casing 46 is capable of a limited reciprocatory movement in the retaining sleeve48, and is normally pressed outwardly by a coiled spring 56 surrounding the rear end of the casing 46 and abutting the rear side of the flange 54.

This casing 46 is provided with a front end wall 57 having a central opening 58. In the outer face of said Wall 57 are radial grooves 59 that receive the cutting flanges of the steel bit. Operating in the bushing 45 and casing 46 is the tappet 60 adapted to be struck by the piston hammer. 43 and carrying at its front end a dolly 61 through the medium of the stem- 62, said dolly fitting into a socket 63 formed in the front end of the tappet. The dolly has its front end .cupped, as shown at 64.

With this structure, the steel is placed with its cutting flanges in the grooves 59 and the'casing is pressed rearwardly against the action of the spring 56 so asto bring the die endof the dolly against the steel. The hammering action of the piston on the tappet is transmitted to the dolly and contracts the discharge end of the bore of the steel by insetting the metal around the same in a manner already described.

From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art without further description and it will be under stood that various changes in the size, shape, proportion and minor details of construction may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

What I claim, is

.1; In a structure of the character set forth, the combination 'with a chambered casing, the chamber of said casing having a front wall provided with an opening of less diameter than the chamber, of a tappet slidable in the chamber of the casing, a, dolly of less cross sectional area than the tappet carried by the front end of the tappet and extending through the opening in the front wall of the chamber, said dolly having its front end formed to inset the metal about the bore of a drill steel bit, and means carried by the exposed side of said front wall forcentering the drill steel bit with respect to the dolly.

2. In a structure of the character set forth, the combination with a chambered casing having inset front wall forming a front wall for the chamber and having an opening of less diameter than the chamber, of a tappet slidable in the chamber ofthe casing, a separate dolly of smaller diameter than the tappet projecting from its front end and extending through the opening in the front wall of the chamber, said dolly having its front end formed to inset the metal about the bore of a drill steel bit, and means carried by said inset front wall' for centering the drillsteel bit with respect to the dolly.

. ber including g 3. The combination with a cylinder mema barrel, of a bushing in the barrel, a chambered casing in front of the bushing and having a front end Wall, a pistonin the barrel, a tappet in the bushing having its rear end in position to be struck by the hammer and having its front end in the chamber of the casing, a dolly fixed in the front end of the tappet and having In testimony a front end that operates through the front end Wall of the casing and is provided with a die formation to contract the metal of a steel bit about the bore of the steel, and bit fiange-receiving grooves in the front end Wall and radiating from the dolly to center a steel bit with respect to said dolly. whereof, I aflix my signature.

GUSTAV O. PEARSON. 

